“…Reviews of the literature cite consistent effects of moderate levels of physical exercise in reducing depression (Griest et al, 1979;Biglan & DOW, 1981 ;Blaney, 1981 ;Antonelli, 1982;Blumenthal et al, 1982; see also Murphy et al, 1972) and anxiety (Vallins, 1966;Morgan, 1976;Greenberg, 1979;Blumenthal et al, 1982;Pauley et al, 1982;Lawrence, 1983; but see Dodson & Mullens, 1969;Morgan, 1974 for long-term effects of regular exercise) and in improving self-concept (Lee, 1957;Nunley, 1965;Layman, 1971 ;Folkins & Sime, 1981 ;Lawrence, 1983). The beneficial effects of exercise on the above variables may be partly explained by the fact that exercise is reported to improve sleep (Baekeland, 1970;Morgan, 1976;Oswald, 1982), may function as a period of 'time out' during the day (Donoghue, 1977;Bahrke & Morgan, 1981), promotes relaxation (DeVries & Adams, 1972;Solomon & Bumpus, 1978;Heide & Borkovec, 1984) [but see Hansen (1976) for exhilaration effects], and improves self-concept (references as above).…”